Field of the Disclosure
The present disclosure relates generally to wireless communication systems and, more particularly, to routing downlink radio bearer packets in a wireless communication system.
Description of the Related Art
Conventional base stations (which may also be referred to as eNodeBs) typically implement two types of processor boards: a controller board and one or more modem boards. A conventional controller board includes a network processing unit (NPU) to terminate a backhaul connection to a core network of the wireless communication system and a second processor that implements a protocol stack for processing protocols such as the packet data convergence protocol (PDCP), the general packet radio service (GPRS) tunneling protocol (GTP), Internet protocol security (IPSec), and the like. No baseband processing is typically performed on the conventional controller board. Instead, the modem board performs baseband processing of signals received over the air interface or signals to be transmitted over the air interface. The modem board includes one or more digital signal processors (DSPs) to handle physical layer (or Layer 1) operations and a separate multi-core processor is used to perform higher layer (e.g., Layer 2 and Layer 3) operations. The controller board and the one or more modem boards each require additional dedicated devices such as read-only memory (ROM), random access memory (RAM) that may be implemented using double data rate (DDR) memory, or flash memory to store generic applications, an operating system image, and the like. Interfaces must also be provided between the controller board and the one or more modem boards. Each conventional modem board with a multi core processor and DSPs can support up to three carriers, so a base station with three modem boards can support up to nine carriers and approximately 2000 connected users.